using only the 1 fx5 leaves you just over 1000L/PH short by my calculations the tanks about 630lts-140uk gallons that x 5 = 3150L/PH which is the minimum turnover you need for those fish really
this is some info i found when researching for my tank
Manufactuers rate their filters by the maximum produced by the pump under ideal conditions without media and things like hoses which isn't very helpful in the real world. Most cannisters seem to get less then 50% of their rated flow capacity when used in the real world
The Fluval showed a flowrate of 1991 litres per hour when full of media and connected which is about 57% of its rated pump capacity of 3500 l/ph
Turnover is very redundant, more lph turnover can be added by simply adding a powerhead to the tank. Something like a koralia for instance. The media capacity of the FX5 should be plenty in relation to the fish kept .. ie. to hold a withstandable amount of bacteria to cope with the bioload.
What markandhisfish mentioned about a second is a far more feasible option, as mentioned if one fails at least the other can semi cope with the load while sorting the other filters problems.
GG, the tank is stunning and fingers crossed all the fish stay happy and aggressive free
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